National Grid References

Kitchin's Hampshire 1751
NGRs Simple mathematics was used to crudely superimpose the national grid on Kitchin's map. The difference between the map projections used by the NGR system and used Thomas Kitchin has been ignored. 'Centres' of the the old map and the Ordnance Survey map of the county were superimposed at an average position of twenty or so prominent towns; the orientations and scales were matched by averaging the directions and distances of these places from the centres on each map; it is then possible to draw the NGR from the modern map upon the image of the old. The calculations were done by a computer using a program written by MN, OLDMAPS.exe; fuller notes about the process are provided in the software notes, OLDMAPS.rul.

File KIT2PTS.txt has readings of positions of recognisable places on the old map, using (x,y) coordinates on the old map. And file KIT2NGR.txt has the results of the calculations:-

Points
file		 



@t Kitchin 1751 large

@pl Alton @ngr SU717396 @xy (66.65,47.34)
@pl Andover @ngr SU365458 @xy (43.04,50.85)
@pl Basingstoke @ngr SU634527 @xy (62.07,54.66)
@pl Burghclere @ngr SU469610 @xy (48.87,59.02)
@pl Buriton @ngr SU740200 @xy (63.77,35.50)
@pl Christchurch @ngr SZ159925 @xy (24.34,19.45)
@pl Fareham @ngr SU575061 @xy (56.00,27.58)
@pl Fordingbridge @ngr SU150145 @xy (29.67,31.27)
@pl Grately @ngr SU275420 @xy (35.64,47.61)
@pl Havant @ngr SU717062 @xy (64.27,26.72)
@pl Kingsclere @ngr SU525586 @xy (52.29,59.12)
@pl Lymington @ngr SZ322954 @xy (33.82,20.77)
@pl Nether Wallop @ngr SU304364 @xy (37.69,44.24)
@pl Odiham @ngr SU740509 @xy (67.58,53.88)
@pl Overton @ngr SU514500 @xy (52.78,54.99)
@pl Petersfield @ngr SU744235 @xy (64.12,37.69)
@pl Romsey @ngr SU351212 @xy (39.98,37.79)
@pl Stockbridge @ngr SU355351 @xy (42.29,43.43)
@pl Tangley @ngr SU334524 @xy (41.61,55.52)
@pl Whitchurch @ngr SU460478 @xy (50.27,54.03)
@pl Winchester @ngr SU478293 @xy (47.75,40.00)

@w 82.56 @h 63.56

@sc 11.85 @m 12

NGR
file		 


file: KIT2NGR.txt

Map 

 Data file: KIT2PTS.txt
Output file: KIT2NGR.txt


OLDMAPS

Plotting a NGR grid on an old map
version 7.1
MN: 30.8.1999


Given points

 no place                     ngr         (x,y)

  1  Alton                    SU717396    (   66.65,   47.34)
  2  Andover                  SU365458    (   43.04,   50.85)
  3  Basingstoke              SU634527    (   62.07,   54.66)
  4  Burghclere               SU469610    (   48.87,   59.02)
  5  Buriton                  SU740200    (   63.77,   35.50)
  6  Christchurch             SZ159925    (   24.34,   19.45)
  7  Fareham                  SU575061    (   56.00,   27.58)
  8  Fordingbridge            SU150145    (   29.67,   31.27)
  9  Grately                  SU275420    (   35.64,   47.61)
 10  Havant                   SU717062    (   64.27,   26.72)
 11  Kingsclere               SU525586    (   52.29,   59.12)
 12  Lymington                SZ322954    (   33.82,   20.77)
 13  Nether Wallop            SU304364    (   37.69,   44.24)
 14  Odiham                   SU740509    (   67.58,   53.88)
 15  Overton                  SU514500    (   52.78,   54.99)
 16  Petersfield              SU744235    (   64.12,   37.69)
 17  Romsey                   SU351212    (   39.98,   37.79)
 18  Stockbridge              SU355351    (   42.29,   43.43)
 19  Tangley                  SU334524    (   41.61,   55.52)
 20  Whitchurch               SU460478    (   50.27,   54.03)
 21  Winchester               SU478293    (   47.75,   40.00)
number of points = 21



Centroids of points

 (x,y) centroid is  (   48.79,   42.93)
  NGR centroid is  SU472324
    numerical ngr  447.28 132.43



Map scale

scale =     1.38 (Alton)
scale =     1.75 (Andover)
scale =     1.46 (Basingstoke)
scale =     1.76 (Buriton)
scale =     1.50 (Christchurch)
scale =     1.67 (Fareham)
scale =     1.65 (Fordingbridge)
scale =     1.57 (Grately)
scale =     1.60 (Havant)
scale =     1.61 (Kingsclere)
scale =     1.50 (Lymington)
scale =     1.55 (Nether Wallop)
scale =     1.49 (Odiham)
scale =     1.42 (Overton)
scale =     1.76 (Petersfield)
scale =     1.62 (Romsey)
scale =     1.68 (Tangley)
scale =     1.38 (Whitchurch)
scale =     1.02 (Winchester)

map scale  1 to   154647
  (range   102177 to   176232)

or         1 to   154000



Map heading

Map heading
NGR north on map is  0.2 degrees from map north



Check points

 no  place                    true        map
                              ngr         ngr

  1  Alton                    SU717396    SU748393  error 3.11
  2  Andover                  SU365458    SU383446  error 2.16
  3  Basingstoke              SU634527    SU677506  error 4.79
  4  Burghclere               SU469610    SU473573  error 3.72
  5  Buriton                  SU740200    SU704210  error 3.74
  6  Christchurch             SZ159925    SZ096959  error 7.16
  7  Fareham                  SU575061    SU585087  error 2.79
  8  Fordingbridge            SU150145    SU177142  error 2.72
  9  Grately                  SU275420    SU269395  error 2.57
 10  Havant                   SU717062    SU713074  error 1.26
 11  Kingsclere               SU525586    SU526574  error 1.20
 12  Lymington                SZ322954    SZ242980  error 8.41
 13  Nether Wallop            SU304364    SU301343  error 2.12
 14  Odiham                   SU740509    SU762494  error 2.66
 15  Overton                  SU514500    SU533511  error 2.20
 16  Petersfield              SU744235    SU710244  error 3.52
 17  Romsey                   SU351212    SU336244  error 3.53
 18  Stockbridge              SU355351    SU372331  error 2.62
 19  Tangley                  SU334524    SU361518  error 2.77
 20  Whitchurch               SU460478    SU495496  error 3.94
 21  Winchester               SU478293    SU456278  error 2.66


Map sheet corners

 bottom left SY720657
    top left ST717640
   top right SU993645
bottom right SZ997662



Grid lines

x positions on bottom and top edges,
y positions on left and right edges,
by which to draw lines on map

easting grid lines

Eing      bottom edge    top edge

 380          5.12           5.36
 390         11.59          11.83
 400         18.05          18.29
 410         24.52          24.76
 420         30.99          31.23
 430         37.45          37.69
 440         43.92          44.16
 450         50.38          50.62
 460         56.85          57.09
 470         63.32          63.56
 480         69.78          70.02
 490         76.25          76.49
 500         82.72          82.96

northing grid lines

Ning      left edge      right edge
  70          2.74           2.43
  80          9.21           8.90
  90         15.67          15.36
 100         22.14          21.83
 110         28.61          28.30
 120         35.07          34.76
 130         41.54          41.23
 140         48.01          47.70
 150         54.47          54.16
 160         60.94          60.63
 170         67.41          67.09



Grid baselines

10Km square corner with
northsouth and westeast grid line points,
by which to draw lines on map

  NGR base point  SU472324
  x,y base point  (   44.07,   41.37)

        mark x,y  (   44.10,   47.84)
        mark x,y  (   44.12,   54.31)
        mark x,y  (   44.15,   60.77)
        mark x,y  (   44.17,   67.24)

        mark x,y  (   44.05,   34.91)
        mark x,y  (   44.03,   28.44)
        mark x,y  (   44.00,   21.98)
        mark x,y  (   43.98,   15.51)
        mark x,y  (   43.95,    9.04)
        mark x,y  (   43.93,    2.58)
        mark x,y  (   43.90,   3.89)

        mark x,y  (   50.54,   41.35)
        mark x,y  (   57.01,   41.33)
        mark x,y  (   63.47,   41.30)
        mark x,y  (   69.94,   41.28)
        mark x,y  (   76.41,   41.25)
        mark x,y  (   82.87,   41.23)

        mark x,y  (   37.61,   41.40)
        mark x,y  (   31.14,   41.42)
        mark x,y  (   24.68,   41.45)
        mark x,y  (   18.21,   41.47)
        mark x,y  (   11.74,   41.50)
        mark x,y  (    5.28,   41.52)
        mark x,y  (   1.19,   41.55)



Scale line

scale line length    11.85 cm
representing   12 miles
scale 1 to   162972


Kitchin's Hampshire 1751 (larger), index grid
General index
Old Hampshire Mapped
Map HMCMS:CRH1958.90